BOSTON — In a season that has had its share of disappointment for the Celtics, few stick out like the struggles they have had with the Milwaukee Bucks this season. Twice the two have tangled and the Bucks came away victorious in both instances.

For various reasons, the Bucks have been the one team that the Celtics have consistently come up short against even though Milwaukee owns the worst record in the league.

"We just have to get over the hump," said Celtics foward Jared Sullinger. "We have to come out, play hard and not play against the record or the competition or anything like that. We need to win this game going forward."

And doing so will be a bit tougher with Rajon Rondo (rest) not playing. His backcourt mate Avery Bradley has missed six of the Celtics' last nine games with a right ankle sprain, but he's scheduled to go as well.

Regardless of who plays, the Celtics have to approach tonight's game with a must-win mentality.

"We let them get two of them," Sullinger sais. "We have to come out and get this one."

Here are some other keys to tonight's game:

WHAT TO LOOK FOR: Boston has lost two of three to Milwaukee this season, with bench scoring being a key factor in all three games. The Celtics' second unit has been outscored by the Bucks' backups 121-69, or 17.3 points per game. It's hard to compete -- let alone beat -- a team whose second unit dominates like that.

MATCHUP TO WATCH: Brandon Bass vs John Henson

Brandon Bass (6 points, 2 rebounds) was among the many Celtics to struggle against the Mavs' frontcourt that has lots of length. He'll see more of the same tonight in 6-foot-11 John Henson who is having a solid season with 11.8 points and 8.1 rebounds per game.

PLAYERS TO WATCH: With Jared Sullinger drawing more attention, opportunities for Jeff Green should become more plentiful. Getting him off to a good start, preferably going to the basket, will bode well for Boston's chances of evening up this series.

STAT TO TRACK: Defending the three-point shot has been an issue most of the season for the Celtics. Few teams have lit the Celtics up from three-point range the way the Bucks have this season. Despite shooting 35.1 percent on the season, the Bucks have connected on an impressive 44 percent (22-for-50) of their threes against Boston in three games.

A. Sherrod Blakely serves as Comcast SportsNet's NBA Insider. Read more from Sherrod here, or follow him on Twitter or Facebook.